Process of making molded articles.



106. COMPOSITIONS,-

COATING R PLASTIC No Drawing.

- cuss REFERENCE UNITED STATES PATENT OFFICE.

JAMES P. A. MCCOY, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

PROCESS OF MAKING MOLDED ARTICLES.

To all whom it may concern; 4

Be it known that I, JAMEs P. A. MCCOY, a subjectof the King of Great Britain, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Processes of Making Molded Articles, of which the following is a specification.

My invention relates tomolding processes, and it has special reference to the manufacture of molded articles from Portland cement and other similar materials.

The object of my invention is to provide a process which may be readily and cheaply practised and which produces molded articles of superior hardness and strength, as compared with the articles which have been molded heretofore from cement.

It is well known that the addition of a solution of sodium silicate or potassium silicate to Portland cement and similar cemcntitious materials results in a composition that is very hard and strong, upon setting. Such a mixture, however, hardens so rapidly that there is not sufiicient time between the mixing and setting of the composition to allow for molding, and therefore, it has not been considered possible to take advantage of the hardness and strength of the cementsilicate mixture in making molded articles.

cement and form an indurated mass.

The proportion in which the dry sodium or potassium silicate is added to the cementdepends upon the rapidity with which it is desired that the mixture shall harden. I have found-that 1% by weight of sodium silicate. or even less" .n this amount, may be used when the time of hardenin is to be retarded as much as possible and w en great ultimate hardness is not required. When themass is to be as hard as possible, and when very rapid hardening is not objection- I Specification of Letters Patent.

Application filed July 3, 1914. Serial No. 848,805.

Patented Dec. 3, 1918.

able, I may use as much as 20;; by wei ht of sodium silicate. The percen ages give n are based upon the weight of dry cement emloye'd.

The fillers mentioned above may be of any of the materials commonly used for this purpose and these fillers may be incorporated in the cement mixture in any suitable proportions.

The molding material prepared in the manner described above may be handled in any well known or convenient manner, and with any suitable apparatus, for making molded articles. It is, of course, desirable that the amount of liquid present during the molding be kept as low as possible, and the exact amount of moisture necessary in this stage of the process may be readily determined for a given batch of cement by a few preliminary experiments.

In practising my present invention, it is possible to make use of any water-soluble silicate in connection with any cementitious material that can be indurated by means of the soluble silicates; Itis therefore to be understood that the foregoing references to sodium silicate and Portland cement are merely illustrative. and that no limitations are to be imposed upon my invention except such as are indicated in the appended claims.

I claim as my invention:

1. A process of making molded articles that comprises making a dry mixture of sodium silicate and Portland cement, moistening the mixture sufliciently for molding but not sufficiently to substantially dissolve,

the silicate, molding the moistened mass and subjecting the molded articles to the action of steam.

2. A process of making molded articles that comprises making a dry mixture of a water-soluble silicate and Portland cement, moistening the mixture sufficiently for moldmg but not sufiiciently to enable the silicate to react appreciably with the cement, moldmg the moistened mass, and subjecting the molded articles to the action of steam.

3. A process of making molded articles that comprises making a dry mixture of sodium silicate, Portland cement and a filler, moistening the mixture sufiiciently for moldmg but not sufliciently to enable the silicate to react appreciably with the cement, mold mg the moistened mass, and subjecting the molded articles to the action of steam.

Examiner 2 tsetse 4. A process 'of making molded articles that comprises making a dry mixture containing sodium silicate and a cementitious material, the cementitious material constituting the major portion of the total mixture, moistening the mixture sufliciently for molding but not sufliciently to enable the silicate to react appreciably with the cementitious -mit the mixture to be molded without subjecting the molded articles to the action of steam.

6. A process of making molded articles that comprises making a dry mixture of a Water-soluble silicate and a cementitious material, the latter constituting the major portion of the mixture, 'moistening the mixture suificiently for molding but not sufliciently to substantially'dissolve thesilicate, molding the moistened mass and subjecting the molded articles to the action of steam.

In testimony whereof, I have hereunto subscribed my name this 30th day of June.

- JAMES P. A. MCCOY.

Witnesses:

W. H. KELHTON, B. B. Hmns. 

